The present invention relates to a steering wheel having a skeleton provided with a foamed sheathing, a hub, spokes and a steering wheel rim, and including a gas bag module which is inserted in a central recess of the steering wheel, with a cover cap at the side facing the driver.
Numerous proposals have already been made for securing a gas bag module in a steering wheel. When steering wheels in the final assembly are secured by means of a nut screwed to the end of the steering column, the gas bag module cannot be inserted until the steering wheel has been fitted since the module is located centrally above the steering wheel hub which must remain freely accessible for screwing on the nut. Alternatively, when the steering wheel is furnished with the completely assembled gas bag and is mounted to the steering column, then some other means of securing the steering wheel is needed. For this, proposals have already been made as well, but all of which are more expensive in design and thus more costly than the usual solution of securing the steering wheel by a central nut.
If the gas bag cover is to be used for actuating the horn switch, the gas bag module needs to be shiftably arranged in the steering wheel, allowing for a contact stroke parallel to the steering wheel axis.
With many mounting systems for gas bag module in a steering wheel, it is a nuisance that the cover cap on the side facing the driver may be positioned relative to the surface of the steering wheel only with considerable complication such that movement gaps existing between the cover cap and the steering wheel, as needed for actuating the horn switch, are equally wide, because between any fastening points at which bolts are inserted and these portions in which movement gaps are provided, a plurality of components is arranged whose inevitable production tolerance in the worst case add up, resulting in significantly differing wide movement gaps. This is unacceptable in terms of a neat appearance.
An object of the invention is to provide a steering wheel with a fastening means permitting to maintain any movement gaps within close tolerances, using conventional bolt connections to reduce production cost, and without necessitating additional space.
To achieve this object it is proposed in accordance with the invention that mounting studs are provided which extend parallel to the steering wheel axis. The positioning of these studs is defined and determined by a foamed sheathing which covers the steering wheel rim and at least part of the spokes. The cover cap has recesses wherein free ends of the mounting studs are slidingly received.
In this arrangement it is assumed that the constructional alignment coordinates, for correctly positioning the cover cap relative to the steering wheel surface, need to be provided as near as possible to the movement gaps and where possible in the same component which in conjunction with the cover cap itself is responsible for the width of the movement gap to be judged by appearance only. This is the foamed sheathing applied to the steering wheel. When in accordance with the invention the portions juxtaposing the cover cap are produced in the same mold and in the same step of production as the coordinates determining the positioning, then the production tolerances may be reduced to such an extent that they are no longer able to influence the movement gaps.
The mounting studs to be used in accordance with the invention are accordingly positioned in the foamed sheathing and so precisely determine the positioning of the cover cap which in turn is attachable to the mounting studs by the guide recesses in the cover cap. It will readily be appreciated that the movement gaps may be very closely toleranced in this way, particularly when the mounting studs are arranged directly juxtaposing the movement gaps where possible.
The gas bag module may be preassembled with the cover cap via the mounting studs and then inserted together with the cover cap in the steering wheel already arranged in the vehicle. Subsequently, all that is needed is to tighten the studs on the rear side of the steering wheel, this corresponding to the present scope of work in fitting bolt connections.